Synthesis of novel octahedral silicon compounds; Synthesis of Bis[3-(1-{[aryl(hydroxy)methylene]hydrazinylidene}ethyl)-6-methyl-2-oxo-2 H -pyran-4-olato- N, O, O ′]silicon(IV)

Article abstract of DOI:10.1055/s-0033-1338924

The synthesis of new silicon compounds is reported via the cyclization of dehydroacetic acid N-acylhydrazones with silicon tetraacetate. The procedure involves formation of new octahedral hexacoordinated silicon structures.

Full text of DOI:10.1055/s-0033-1338924

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PAPER
paper
Synthesis of Novel Octahedral Silicon Compounds; Synthesis of
Bis[3-(1-{[aryl(hydroxy)methylene]hydrazinylidene}ethyl)-6-methyl-
2-oxo-2H-pyran-4-olato-N,O,O′]silicon(IV)
Synthesis of Novel Octahedral Silicon Compounds
Sotiria Karamouzi,a Anna Maniadaki,a Despina A. Nasiopoulou,a Elvira Kotali,a Antigoni Kotali,*a Philip A. Harris,b
James Raftery,c John A. Joulec
a
Laboratory of Organic Chemistry, Department of Chemical Engineering, University of Thessaloniki, Thessaloniki 54124, Greece
Fax +30(231)0996253; E-mail: kotali@eng.auth.gr
b
GlaxoSmithKline, 1250 South Collegeville Road, P.O. Box 5089, Collegeville, PA 19426-0989, USA
c
The School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
Received: 13.12.2012; Accepted after revision: 06.05.2013
This finding is extremely promising since it has been
Abstract: The synthesis of new silicon compounds is reported via
proved that structural transition metals can be replaced by
the cyclization of dehydroacetic acid N-acylhydrazones with silicon
an inert octahedral silicon. The synthesis of these interest-
tetraacetate. The procedure involves formation of new octahedral
ing molecules was achieved via reaction of 1,10-phenan-
throline with silicon tetraiodide and subsequent treatment
with o-dihydroxyarenes.3
hexacoordinated silicon structures.
Key words: octahedral silicon, dehydroacetic acid, N-acylhydra-
zones, silicon tetraacetate, hypervalent silicon
Hexacoordinated silicon complexes have also been re-
cently reported to have been obtained from O,N,O′-chelat-
ing Schiff base ligands, derived from condensation of
salicylaldehyde or o-hydroxyacetophenone with either an
amino alcohol,5 ketone,6 ester,7 or amide,8 and subsequent
treatment with silicon tetrachloride.
Consequently, our interest in oxygen heterocycles9 as well
as in the use of hydrazones10 as starting materials prompt-
ed us to design novel organosilicon derivatives of oxygen
heterocycles and specifically structures such as 5 accord-
ing to Scheme 1.
It is well known that most organosilicon compounds con-
tain a tetracoordinate silicon atom. Silicon is the next
higher congener of carbon, but it has the advantage that it
can exist in hypervalent states. Due to the empty 3d orbit-
als, the central silicons are thought to carry more than
eight electrons in the valence shell.1–3 Theoretical studies
of hypervalent molecules recommend the ‘three-centers
four-electrons’ bonding approach as an alternative to ra-
tionalize the geometries of these molecules.4 Thus the co-
ordination number of silicon can increase to five or six
especially when the silicon atom is surrounded by electro-
negative substituents. In recent decades, studies on penta-
and hexacoordinated derivatives were valuable to theoret-
ical, synthetic, medicinal, and applied chemistry.2 Recent-
ly, Meggers et al. reported the synthesis of
hexacoordinated octahedral silicon derivatives that were,
interestingly, found to be hydrolytically stable and of pos-
sible use in the design of DNA intercalators.3 A character-
istic example, compound 1, is shown in Figure 1.
NHCOR
N
HO
COMe
O
HO
MeOH
reflux, 2 h
+
RCONHNH2
O
O
95–98%
3
O
2
4
Si(OAc)4, THF
0 °C to r.t., 24 h
26–45%
O
2+
O
N
R
N
Si
N
N
O
O
O
O
O
N
Si
O
N
N
N
R
O
O
5
1
Scheme 1 Synthesis of silicon compounds 5
Figure 1 Silicon bioactive DNA intercalator
To our knowledge, no such structures have been reported
in the literature and we now report the synthesis of hexa-
coordinated silicon derivatives 5.
SYNTHESIS 2013, 45, 2150–2154
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DOI: 10.1055/s-0033-1338924; Art ID: SS-2012-N0808-OP
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Synthesis of Novel Octahedral Silicon Compounds
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Initially a series of N-acylhydrazones of dehydroacetic the corresponding silicon heterocycles 5 in fair to good
acid (DHA, 3-acetyl-4-hydroxy-6-methyl-2H-pyran-2- yields, 26–45%. All the reactions were also performed un-
one, 2) were chosen as starting materials. It was envisaged der reflux, however the optimum yields were obtained at
that the N-acylhydrazones would react with silicon tet- room temperature. Hydrazones 4 were purified by recrys-
raacetate [strictly: acetic acid, 1,1′,1′′,1′′′-tetraanhydride tallization from ethanol, whereas the desired silicon com-
with silicic acid (H4SiO4)] to produce the desired systems. pounds 5 were isolated by column chromatography, and
Dehydroacetic acid (2) is a versatile starting material for they were found to be stable at room temperature. The op-
the synthesis of a wide variety of heterocyclic ring timum reaction conditions and the yields and melting
systems. Moreover, dehydroacetic acid complexes of ru- points of new compounds 4 and 5 are presented in Table 1.
thenium(II) and ruthenium(III) containing triphenylphos-
Products 4 and 5 are new compounds and their structures
phine/triphenylarsine have been reported to bind with
1
were established by examination of their IR, H and 13C
DNA.11 Additionally, silicon tetraacetate is a mild, non-
NMR, and mass spectra as well as by either their elemen-
toxic reagent that has found interesting applications, for
tal analysis or high resolution mass measurement of their
example as a precursor for silica nanotubes.12 However,
molecular ions. All spectroscopic data and mass spectra
there are a very limited number of references concerning
match the expected products. Furthermore, 29Si NMR was
its reactivity towards organic substrates. It has been re-
performed on derivative 5d. The characteristic signal ap-
ported that silicon tetraacetate reacts with semicarbazones
peared at δ = –177.4 and this is in accordance with litera-
and thiosemicarbazones to form Si(OAc)2L and SiL2 re-
ture analogues of hexacoordinated silicon.5b,18 In addition,
spectively.13 These have been found to be monomeric in
X-ray diffraction analysis of compound 5d was carried
boiling chloroform and it has been suggested that in diace-
out. The structure that was found by X-ray crystallogra-
toxysilicon compounds, the central silicon atom is penta-
phy is shown in Figure 2. The silicon atom is coordinated
coordinated.13 Silicon tetrachloride and silicon
by four oxygen atoms and two nitrogen atoms. The four
oxygen ligands are in a plane, with the nitrogens attached
above and below generating octahedral geometry.
tetrabromide were used in reactions with 2,2′-azodiphenol
salts, producing neutral products with stoichiometry
Si(L)2 and assigned octahedral structures with four oxy-
Concerning the mechanism of the cyclization, it should be
noted firstly that three nucleophilic centers from the start-
ing hydrazone are ultimately associated with a central sil-
icon atom; two oxygens and the imine nitrogen. The first
step must involve one of these centers displacing acetate
from silicon, presumably via a pentavalent silicon inter-
mediate (not shown).
Recalling the strength of oxygen–silicon bonds,19 we sug-
gest that this first step involves attack by the rather acidic
phenolic hydroxy of the dehydroacetic acid fragment in 4
gens and two nitrogens associated with the silicon.14–18
However, in only the most recent of these studies18 was an
X-ray structural confirmation provided.
Commercially available aryl, alkyl, or heterocyclic carbo-
hydrazides 3 were reacted with dehydroacetic acid (2), to
prepare the hydrazones 4. The molar ratio of the reactants
was 1:1 and the reaction was performed under reflux in
methanol for two hours to yield hydrazones 4a–e in very
good yields. Reaction of hydrazones 4 with silicon tet-
raacetate in tetrahydrofuran at room temperature afforded
Table 1 Preparation of Hydrazones 4 and Silicon Derivatives 5
Product
R
Starting materials
Molar ratio
Time (h)
Solvent
Temp
Yield (%)
Mpa,b (°C)
4a
4b
4c
4d
4e
5a
5b
5c
5d
5e
4-MeC6H4
4-ClC6H4
Bn
2 + 3a
1:1
2
2
MeOH
MeOH
MeOH
MeOH
MeOH
THF
reflux
reflux
reflux
reflux
reflux
r.t.c
95
98
97
96
98
30
43
45
37
26
225
2 + 3b
1:1
214
2 + 3c
1:1
2
139–140
200–201
170–171
>300
2-O2NC6H4
2-thienyl
4-MeC6H4
4-ClC6H4
Bn
2 + 3d
1:1
2
2 + 3e
1:2.5
1:2.5
1:2
2
4a + Si(OAc)4
4b + Si(OAc)4
4c + Si(OAc)4
4d + Si(OAc)4
4e + Si(OAc)4
24
24
24
24
24
THF
r.t.c
>300
1:2.5
1:1.5
1:1.1
THF
r.t.c
>300
2-O2NC6H4
2-thienyl
THF
r.t.c
>300
THF
r.t.c
>300
a Melting points are uncorrected.
b Compounds 4a–e were recrystallized (EtOH).
c The addition of Si(OAc)4 was carried out in an ice bath.
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2013, 45, 2150–2154

2152
S. Karamouzi et al.
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Next we envisage interaction of the imine nitrogen with
the silicon, as indicated in C, which would position the
amide oxygen so that it can attack at silicon, with loss of
a second acetic acid unit producing D, which is ‘half’ of
the final structure. A repeat of the sequence, now starting
with D and reacting with a second molar equivalent of 4
would then lead to 5.
This octahedral complex 5d appears to be hydrolytically
stable in water–dimethyl sulfoxide (4:6) at room temper-
ature under daylight as monitored by HPLC over 24
hours.
In conclusion, we have presented a convenient and gener-
al method for the straightforward preparation of novel
neutral octahedral hexacoordinated silicon derivatives in
fair to good yields. Silicon tetraacetate has been used for
the first time for the synthesis of octahedron silicon com-
pounds and it has been proved to be an effective reagent.
The novel silicon compounds could possibly serve as use-
ful bioactive scaffolds since they combine three related bi-
ological features in their structure: (1) the octahedral
geometry, (2) the bioactive dehydroacetic acid part, as
well as (3) the bioactive hydrazonic part (C=N–N–).20
Figure 2 X-ray structure of 5d. The four Si–O bond lengths vary
from 1.743(2) to 1.774(1) Å while the two Si–N bonds are identical,
at 1.869(2). The angles at Si for cis ligands vary from 84.13(7) (O3–
Si1–N3) to 93.00(7) (O6–Si1–N3). Viewed along the N3–Si1–N6 ax-
is, roughly edge on to the planes of the ligands, the molecule resem-
bles a cross; the planes of the nitro groups are well out of the planes
of the benzene rings to which they are attached.
All solvents for reactions and chromatography were purchased from
Merck; dehydroacetic acid (2), all hydrazides 3 as well as Si(OAc)4
were purchased from Aldrich. TLC plates were Merck plastic plates
with silica gel 60 F254 (70–230 mesh). Column chromatography was
performed on silica gel 60 F254 (70–230 mesh). IR spectra we re-
corded on a Nicolet 200 FT-IR spectrophotometer, 1H and 13C NMR
spectra were recorded on a Bruker Avance 400 spectrometer (1H
MHz 400.15, 13C 100.62 MHz) in DMSO-d6 using the signal of the
solvent as the internal standard [residual DMSO (1H): δ = 2.50,
(13C) δ = 39.5). The 29Si NMR spectrum was recorded on a Bruker
Avance III 700 spectrometer (139.1 MHz) in CDCl3, external TMS
reference; inverse gated decoupling was used to avoid NOE. Either
elemental analysis or HRMS have been provided for all new com-
pounds 4 and 5.
on silicon (arrows on A) to produce an intermediate B,
perhaps with proton removal by the adjacent imine nitro-
gen (Scheme 2).
R
N
R
N
O
H
O
H
O
H
O
Dehydroacetic Acid N-Acylhydrazones 4; General Procedure
Dehydroacetic acid (2, 5 mmol) and a hydrazide 3 (molar ratio 1:1)
were heated at reflux in MeOH (20 mL) for 2 h. The mixture was
allowed to cool and the precipitate that formed was filtered off and
dried under vacuum in a desiccator to afford pure N-acylhydrazones
4 as white solids in very good yields (Table 1).
(AcO)3Si
N
O
N
O
AcO Si(OAc)3
O
O
– AcOH
A
B
Dehydroacetic Acid N-(4-Tolylcarbonyl)hydrazone (4a)
White solid, pure product; yield: 4.75 mmol (95%).
R
R
IR (KBr pellet): 3147, 2949, 1714, 1679, 1537, 1463, 1295 cm–1.
O
AcO
1H NMR (400 MHz, DMSO-d6): δ = 2.13 (s, 3 H), 2.39 (s, 3 H), 3.06
(s, 3 H), 5.87 (s, 1 H), 7.36 (d, J = 7.9 Hz, 2 H), 7.83 (d, J = 8.1 Hz,
2 H), 11.54 (s, 1 H), 15.95 (br, 1 H).
13C NMR (100 MHz, DMSO-d6): δ = 17.5, 19.7, 21.6, 95.3, 106.6,
128.4, 128.9, 143.3, 162.9, 163.6, 165.1, 171.5, 182.7.
O
N
N
+
H
O
AcO
AcO
–
AcO
Si
N
Si
N
AcO O
O
– AcOH
O
O
O
MS (ES+): m/z = 300 (M+).
D
C
Anal. Calcd for C16H16N2O4: C, 63.99; H, 5.37; N, 9.33. Found: C,
63.62; H, 5.28; N, 9.38.
repeat the sequence
with second mol equivalent
of starting 4
Dehydroacetic Acid N-(4-Chlorophenylcarbonyl)hydrazone
(4b)
White solid, pure product; yield: 4.90 mmol (98%).
IR (KBr pellet): 3144, 2936, 1720, 1680, 1593, 1536, 1462 cm–1.
5
Scheme 2 Proposed mechanistic pathway for the formation of struc-
tures 5
Synthesis 2013, 45, 2150–2154
© Georg Thieme Verlag Stuttgart · New York

PAPER
Synthesis of Novel Octahedral Silicon Compounds
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1H NMR (400 MHz, DMSO-d6): δ = 2.14 (s, 3 H), 2.63 (s, 3 H), 5.89
(s, 1 H), 7.36 (dd, J = 8.6, 2.0 Hz, 2 H), 7.94 (dd, J = 8.6, 2.0 Hz, 2
H), 11.70 (s, 1 H), 15.95 (br, 1 H).
1H NMR (400 MHz, CDCl3): δ = 2.16 (s, 3 H), 2.32 (s, 3 H), 3.04
(s, 3 H), 6.10 (s, 1 H), 7.25 (d, J = 8.1 Hz, 2 H), 7.77 (d, J = 8.3 Hz,
2 H).
13C NMR (100 MHz, DMSO-d6): δ = 17.5, 19.7, 95.4, 106.5, 129.2,
13C NMR (100 MHz, CDCl3): δ = 20.0, 21.6, 22.5, 97.3, 103.9,
130.3, 130.7, 137.8, 161.3, 163.7, 164.3, 171.7, 182.5.
126.9, 127.8, 129.8, 142.8, 161.3, 163.0, 168.0, 168.5, 172.6.
MS (ES+): m/z = 320 (M+).
MS (ES+): m/z = 625 (M+ + H).
Anal. Calcd for C15H13ClN2O4: C, 56.17; H, 4.09; N, 8.73; Cl,
11.05. Found: C, 56.12; H, 3.94; N, 8.80; Cl, 11.07.
HRMS: m/z [M + H] calcd for C32H28N4O8Si: 625.1755; found:
625.1753.
Dehydroacetic Acid N-(Benzylcarbonyl)hydrazone (4c)
Bis[3-(1-{[(4-chlorophenyl)hydroxymethylene]hydrazinyli-
dene}ethyl)-6-methyl-2-oxo-2H-pyran-4-olato-N,O,O′]sili-
con(IV) (5b)
White solid, pure product; yield: 4.85 mmol (97%).
IR (KBr pellet): 3269, 3031, 2993, 1668, 1583, 1513, 1470, 1392
cm–1.
1H NMR (400 MHz, DMSO-d6): δ = 2.11 (s, 3 H), 2.54 (s, 3 H), 3.50
(s, 2 H), 5.86 (s, 1 H), 7.25–7.34 (m, 5 H), 11.44 (s, 1 H), 16.17 (s,
1 H).
13C NMR (100 MHz, DMSO-d6): δ = 17.2, 19.7, 95.1, 105.9,
127.25, 128.85, 129.6, 135.3, 162.7, 163.6, 168.2, 168.5, 181.6.
Yellow solid, pure product; yield: 0.215 mmol (43%).
IR (KBr pellet): 1727, 1645, 1590, 1541, 1492, 1450, 1365, 1290,
1226, 1173, 1138, 1090, 1005, 840, 739, 693, 663, 635, 550 cm–1.
1H NMR (400 MHz, CDCl3): δ = 2.17 (s, 6 H), 3.05 (s, 6 H), 6.13
(s, 2 H), 7.52 (d, J = 8.6 Hz, 4 H), 7.88 (d, J = 8.6 Hz, 4 H).
13C NMR (100 MHz, CDCl3): δ = 20.0, 20.1, 97.35, 103.9, 128.4,
129.4, 129.55, 137.45, 161.2, 162.0, 168.9, 169.0, 172.7.
MS (ES+): m/z = 301 (M + H).
MS (ES+): m/z = 665 (M+ + H).
Anal. Calcd for C16H16N2O4: C, 63.99; H, 5.37; N, 9.33. Found: C,
64.12; H, 5.33; N, 9.43.
Anal. Calcd for C30H22Cl2N4O8Si: C, 54.13; H, 3.33; N, 8.42; Cl,
10.66. Found: C, 54.15; H, 3.38; N, 8.06; Cl, 10.38.
Dehydroacetic Acid N-(2-Nitrophenylcarbonyl)hydrazone (4d)
Bis(3-{1-[(1-hydroxy-2-phenylethylidene)hydrazinylidene]eth-
yl}-6-methyl-2-oxo-2H-pyran-4-olato-N,O,O′)silicon(IV) (5c)
Yellow solid, pure product; yield: 0.225 mmol (45%).
White solid, pure product; yield: 4.80 mmol (96%).
IR (KBr pellet): 3148, 2954, 1695, 1592, 1528, 1420, 1393 cm–1.
1H NMR (400 MHz, DMSO-d6): δ = 2.16 (s, 3 H), 2.60 (s, 3 H), 5.95
(s, 1 H), 7.80–7.94 (m, 3 H), 8.21 (d, J = 7.3 Hz, 1 H), 11.96 (s, 1
H), 16.26 (br, 1 H).
13C NMR (100 MHz, DMSO-d6): δ = 17.2, 19.8, 95.5, 105.7, 124.9,
129.9, 130.4, 132.3, 134.7, 147.1, 162.6, 163.6, 164.0, 169.8, 181.4.
IR (KBr pellet): 1718, 1646, 1589, 1493, 1450, 1363, 1287, 1226,
1168, 1090, 1029 1002, 931, 836, 780, 729, 695, 659, 537, 510, 475
cm–1.
1H NMR (400 MHz, CDCl3): δ = 2.16 (s, 6 H), 2.80 (s, 6 H), 3.53
(s, 4 H), 5.71 (s, 2 H), 7.16–7.19 (m, 10 H).
13C NMR (100 MHz, CDCl3): δ = 19.9, 20.05, 37.7, 97.0, 103.7,
MS (ES+): m/z = 332 (M + 1).
127.15, 128.55, 129.3, 135.3, 161.2, 167.95, 168.1, 172.6.
MS (ES+): m/z = 684 (M + Na), 625 (M+ + H).
Anal. Calcd for C15H13N3O6: C, 54.38; H, 3.96; N, 12.68. Found: C,
54.56; H, 3.63; N, 12.64.
Anal. Calcd for C32H28N4O8Si: C, 61.52; H, 4.52; N, 8.97. Found:
C, 61.59; H, 4.42; N, 8.63.
Dehydroacetic Acid N-(2-Thienylcarbonyl)hydrazone (4e)
White solid, pure product; yield: 4.90 mmol (98%).
IR (KBr pellet): 3149, 3089, 1693, 1642, 1564, 1472, 1416, 1363
cm–1.
1H NMR (400 MHz, DMSO-d6): δ = 2.14 (s, 3 H), 2.61 (s, 3 H), 5.88
(s, 1 H), 7.26 (dd, J = 5.0, 3.8 Hz, 1 H), 7.92 (dd, J = 3.8, 1.0 Hz, 1
H), 7.95 (dd, J = 5.1, 1.0 Hz, 1 H), 11.60 (s, 1 H), 15.80 (br, 1 H).
13C NMR (100 MHz, DMSO-d6): δ = 17.5, 19.7, 95.5, 106.4, 128.8,
130.9, 133.3, 135.9, 160.0, 162.8, 163.8, 172.3, 182.5.
Bis[3-(1-{[hydroxy(4-nitrophenyl)methylene]hydrazinyli-
dene}ethyl)-6-methyl-2-oxo-2H-pyran-4-olato-N,O,O′]sili-
con(IV) (5d)
Yellow solid, pure product; yield: 0.185 mmol (37%).
IR (KBr pellet): 1726, 1644, 1574, 1546, 1490, 1449, 1375, 1291,
1224, 1168, 1091, 1033, 1003, 942, 911, 850, 824, 776, 735, 697,
658, 619, 565, 544, 510 cm–1.
1H NMR (400 MHz, CDCl3): δ = 2.10 (s, 6 H), 2.92 (s, 6 H), 6.20
(s, 2 H), 7.75–7.77 (m, 4 H), 7.89–7.94 (m, 4 H).
13C NMR (100 MHz, CDCl3): δ = 19.9, 20.0, 97.2, 104.1, 123.1,
MS (ES+): m/z = 293 (M + 1).
Anal. Calcd for C13H12N2O4S: C, 53.42; H, 4.14; N, 9.58; S, 10.97.
Found: C, 53.23; H, 4.17; N, 9.56; S, 10.71.
124.1, 130.6, 132.8, 133.3, 149.6, 160.6, 161.6, 169.1, 170.4, 173.1.
29Si NMR (139.1 MHz, CDCl3): δ = –177.4.
MS (ES+): m/z = 687 (M+ + H).
Reaction of Hydrazones 4 with Silicon Tetraacetate; General
Procedure
Si(OAc)4 was added to hydrazone 4 (1 mmol) in THF (25 mL), with
stirring, in an ice bath; the molar ratios of hydrazone/Si(OAc)4 are
given in Table 1. The mixture was then stirred at r.t. for 24 h. The
oily product obtained after evaporation of the solvent was subjected
to column chromatography (silica gel 70–230 mesh, petroleum
ether–EtOAc, 1:1) to afford pure silicon heterocycles 5 as yellow
solids in fair to good yields (Table 1).
Anal. Calcd for C30H22N6O12Si·0.8 H2O: C, 51.40; H, 3.39; N,
11.98. Found: C, 51.40; H, 3.03; N, 11.87.
Crystal data: A sample suitable for X-ray analysis was obtained by
recrystallization (CHCl3–petroleum ether). λ = 1.54178 Å; temper-
ature: 100 K; reflections collected/unique: 13257/5562; Complete-
ness to θ = 66.60° 97.0%; space group: P1; a = 10.1004(4) Å; b =
12.0852(5) Å; c = 12.5100(5) Å; α = 86.424(2)°; β = 79.013(2)°;
γ = 82.534(3)°; V = 1485.23(10) Å3; Z = 2; R indices [I > 2s(I)]:
R1 = 0.0426, wR2 = 0.1129; the structure was solved with
SHELXS-97 and refined with SHELXL-97.
Bis[3-(1-{[hydroxy(4-tolyl)methylene]hydrazinylidene}ethyl)-
6-methyl-2-oxo-2H-pyran-4-olato-N,O,O′]silicon(IV) (5a)
Yellow solid, pure product; yield: 0.15 mmol (30%).
IR (KBr pellet): 1738, 1653, 1585, 1538, 1492, 1447, 1359, 1288,
1224, 1175, 1133, 1091, 1005, 933, 900, 813, 725, 663, 548 cm–1.
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2013, 45, 2150–2154

2154
S. Karamouzi et al.
PAPER
The crystallographic data has been deposited at the Cambridge
Crystallographic Data Centre and assigned the code number CCDC
893600.
(5) (a) Boehme, U.; Guenther, B. Inorg. Chem. Commun. 2007,
10, 482. (b) Boehme, U.; Wiesner, S.; Guenther, B. Inorg.
Chem. Commun. 2006, 9, 806.
(6) Seiler, O.; Burschka, C.; Metz, S.; Penka, M.; Tacke, R.
Chem. Eur. J. 2005, 11, 7379.
(7) Warncke, G.; Boehme, U.; Guenther, B.; Kronstein, M.
Polyhedron 2012, 47, 46.
(8) Kaempfe, A.; Kroke, E.; Wagler, J. Eur. J. Inorg. Chem.
2009, 8, 1027.
(9) (a) Kotali, A.; Lafazanis, I. S.; Harris, P. A. Tetrahedron
Lett. 2007, 48, 7871. (b) Kotali, A.; Lafazanis, I. S.; Harris,
P. A. Synthesis 2008, 836. (c) Kotali, A.; Lafazanis, I. S.;
Harris, P. A. Synth. Commun. 2008, 38, 3996. (d) Kotali, A.;
Nasiopoulou, D. A.; Harris, P. A.; Helliwell, M.; Joule, J. A.
Tetrahedron 2012, 68, 761.
(10) (a) Kotali, A. ARKIVOC 2009, (i), 81. (b) Kotali, A.; Kotali,
E.; Lafazanis, I. S.; Harris, P. A. Curr. Org. Synth. 2010, 7,
62. (c) Helliwell, M.; Nasiopoulou, D. A.; Kotali, A.; Harris,
P. A.; Joule, J. A. Acta Crystallogr., Sect. E 2011, 67, o1014.
(11) (a) Girshberg, O.; Kalikhman, I.; Stalke, D.; Kost, D.
THEOCHEM 2003, 661, 259. (b) Kost, D.; Kalikhmann, I.
Acc. Chem. Res. 2009, 42, 303.
Bis[3-(1-{[hydroxy(2-thienyl)methylene]hydrazinylidene}eth-
yl)-6-methyl-2-oxo-2H-pyran-4-olato-N,O,O′]silicon(IV) (5e)
Yellow solid, pure product; yield: 0.13 mmol (26%).
IR (KBr pellet): 1717, 1641, 1581, 1550, 1489, 1450, 1379, 1289,
1224, 1116, 1092, 1032, 1004, 945, 853, 831, 774, 725, 657, 545,
501 cm–1.
1H NMR (400 MHz, CDCl3): δ = 2.17 (s, 6 H), 2.99 (s, 6 H), 6.13
(s, 2 H), 7.12 (dd, J = 5.0, 3.8 Hz, 2 H), 7.62 (dd, J = 3.79, 1.26 Hz,
2 H), 7.82 (dd, J = 3.79, 1.26 Hz, 2 H).
13C NMR (100 MHz, CDCl3): δ = 19.9, 20.0, 97.3, 103.9, 128.8,
132.5, 132.6, 159.8, 161.2, 167.8, 172.5.
MS (ES+): m/z = 632 (M + Na), 609 (M + H).
Anal. Calcd for C26H20N4O8S2Si: C, 51.31; H, 3.31; N, 9.21; S,
10.52. Found: C, 50.98; H, 2.96; N, 9.01; S, 10.14.
Acknowledgment
(12) Chitrapriya, N.; Mahalingam, V.; Zeller, M.; Jayabalan, R.;
Swaminathan, K.; Natarajan, K. Polyhedron 2008, 27, 939.
(13) Chen, X.; Berger, A.; Ge, M.; Hopfe, S.; Dai, N.; Gösele, U.;
Schlecht, S.; Steinhart, M. Chem. Mater. 2011, 23, 3129.
(14) Singh, R. V.; Tandon, J. P. Indian J. Chem., Sect. A 1980, 19,
602.
We thank Grazyna Graczyk-Millbrandt (GlaxoSmithKline, Col-
legeville, PA) for conducting the 29Si NMR spectroscopy on 5d.
Supporting Information for this article is available online at
http://www.thieme-connect.com/ejournals/toc/synthesis.SnuIomprifgtooatrinSugpIoi
n
nfomartit
(15) Chavan, S. N.; Inamdar, V. E.; Sunthankar, S. V. Indian J.
Chem. 1975, 13, 808.
(16) Hawaldar, V. S.; Sunthankar, S. V. Indian J. Text. Res. 1980,
5, 20.
(17) Abe, Y.; Nahgao, Y.; Miosono, T. Nippon Kagaku Kaishi
1984, 1128.
(18) Schlecht, S.; Frank, W.; Braun, M. Phosphorus, Sulfur
Silicon Relat. Elem. 2011, 186, 1585.
(19) Weinhold, F.; West, R. Organometallics 2011, 30, 5815.
(20) Rollas, S.; Küçükgüzel, G. Molecules 2007, 12, 1910.
References
(1) Voronkov, M. G.; Trofimova, O. M.; Bolgova, Y. I.;
Chernov, N. F. Russ. Chem. Rev. 2007, 76, 825.
(2) Holmes, R. R. Chem. Rev. 1996, 96, 927.
(3) Xiang, Y.; Fu, C.; Breiding, T.; Sasmal, P. K.; Liu, H.; Shen,
Q.; Harms, K.; Zhang, L.; Meggers, E. Chem. Commun.
2012, 48, 7131.
(4) Cheunga, Y.-S.; Nga, C.-Y.; Chiub, C.-W.; Li, W.-K.
THEOCHEM 2003, 623, 1.
Synthesis 2013, 45, 2150–2154
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